Top clean tech breakthrough of 2008?

To round out the year, the journal Science is highlighting its take on the year’s most important advances in science and technology. Between leaps towards reprogrammable genetic material and understanding color-coded fat cells, scientists also reached a major milestone in solving the problem of solar and wind energy storage.

One major factor holding back the adoption of solar technology is the trouble of storing it so that the sun can provide a constant supply of electricity to buildings and transportation systems. So far, conventional battery chemistries haven’t been able to meet the challenge with sufficiently robust and cost-competitive products—for example, adding batteries to a home solar system could add $10,000 to the price of the set-up.

One suggested alternative is to split water and store the hydrogen in a fuel cell, allowing for the so-called hydrogen economy to arise. That vision, in which hydrogen is compressed and packaged as the energy transfer method of the future, has taken a flogging in recent years for claims that it consumes too much energy to isolate the hydrogen. In nature, water splitting happens as part of photosynthesis. But doing it artificially has been prohibitively energy intensive and requires a good catalyst to simplify the reaction. Fancy metals such as platinum make good catalysts, but the price doesn’t work for large-scale use.

Daniel Nocera, a chemistry professor at MIT who co-authored the paper, created a highly efficient catalyst using phosphorous and cobalt. These two humdrum ingredients are much more accessible than platinum and promise to keep the catalyst cheap and easy to make. Nocera estimates that splitting a few liters of water a day would be enough to power a home. Earlier this year, a Science reporter quoted Thomas Moore, a chemist at Arizona State University as calling the breakthrough "a big-to-giant step in the direction of powering industrial societies with renewable fuels."

There’s still lots of work to be done to speed up the process of splitting water and to reduce the energy inputs even further. But if the catalyst can deliver efficient and affordable energy storage systems, a very different forecast could emerge for solar and wind.

Story by Sandra Upson. This article originally appeared in "Plenty" in December 2008.